The Smith X-99 Prop-Jet was a six-seat

turboprop A turboprop is a Gas turbine, gas turbine engine that drives an aircraft Propeller (aeronautics), propeller. A turboprop consists of an intake, reduction drive, reduction gearbox, gas compressor, compressor, combustor, turbine, and a propellin ...

powered business aircraft designed in the United States in the 1980s. Only one was built.

Design and development

The Prop-Jet was an attempt to produce a small, propeller driven business aircraft capable of cruising at speeds above 350 mph (560 km/h). It was powered by a 550 shp (410 kW)

Pratt & Whitney Canada PT6 The Pratt & Whitney Canada PT6 is a turboprop aircraft engine produced by Pratt & Whitney Canada. Its design was started in 1958, it first ran in February 1960, first flew on 30 May 1961, entered service in 1964, and has been continuously upd ...

engine, mounted in a long nose and driving a four blade,

constant speed propeller Constant or The Constant may refer to: Mathematics * Constant (mathematics), a non-varying value * Mathematical constant, a special number that arises naturally in mathematics, such as or Other concepts * Control variable or scientific con ...

. The

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

was a

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

constructed from

graphite Graphite () is a Crystallinity, crystalline allotrope (form) of the element carbon. It consists of many stacked Layered materials, layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable ...

and glass-fibre

epoxy Epoxy is the family of basic components or Curing (chemistry), cured end products of epoxy Resin, resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide fun ...

sandwich. The pressurised cabin accommodated pilot and five passengers in three rows of seats, with a baggage space behind. Access was by port side doors forward and another over the

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

on the other side. The tail unit was made from

Kevlar Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s as ...

/graphite/glass fibre epoxy sandwich. The fin was swept and the

tailplane A tailplane, also known as a horizontal stabilizer, is a small lift (force), lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters ...

mounted, with anhedral, almost at the top of it. The elevator carried an electrically driven

trim tab Trim tabs are small surfaces connected to the trailing edge of a larger Flight control surfaces, control surface on a boat or aircraft, used to control the trim of the controls, i.e. to counteract hydro- or aerodynamic forces and stabilise the ...

. To speed the completion of the first prototype, the Prop-Jet used the wing and undercarriage of a Beechcraft Baron 58P, though a composite structure wing was envisaged for production aircraft. The Beech wing was a two spar aluminium box structure, without sweep and mounted between mid and low positions with dihedral of 6° and fitted with slotted Fowler flaps. The

tricycle undercarriage Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', that is arranged in a tricycle fashion. The tricycle arrangement has one or more nose wheels in a single front undercarriage and two or more main wheels slightly aft of th ...

was enclosed behind doors after retraction. The Prop-Jet flew for the first time on 29 July 1982. By 1985 Mike Smith was reported as seeking financial backers but only the one prototype Prop-Jet was built.

Specifications

References

{{reflist, refs= {{cite book , title= Jane's All the World's Aircraft 1985-1986, last= Taylor, first= John W. R. , year=1985, publisher= Jane's Information Group, location= London, isbn=0710608217, page=518 {{cite web , url=http://www.aerofiles.com/_sk.html, title=Aerofiles-Smith XP-99 Prop-Jet , access-date=10 October 2012

External links

NACA 23012 airfoil
1980s United States business aircraft Single-engined turboprop aircraft Single-engined tractor aircraft Aircraft first flown in 1982